JPH10273877A - Production of rubber-reinforcing fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a rubber-reinforcing fiber applicable to tires etc., excellent in adhesiveness, heat resistance and fatigue resistance, by treating fiber with the first treating liquid containing a polyepoxide compound, etc., followed by with the specific second treating liquid without any concomitant problems of toxicity or malodor. SOLUTION: This rubber-reinforcing fiber is obtained by treating fiber such as polyester fiber or aromatic polyamide fiber with the first treating liquid containing a polyepoxide compound, blocked polyisocyanate compound, rubber latex and silicate compound, followed by treating the resultant fiber with the second treating liquid containing resorcinol/formaldehyde/rubber latex(RFL) and a water-soluble urethane compound shown by formula I (A is an aromatic polyisocyanate residue; X is a polyol residue; Y is a blocking agent residue; Z is a hydrophilic residue; (1+m) is 2 to 4; (l) and (m) are each >=1; (n) is 1 to 4). Preferably, the second treating liquid is mixed with a compound shown by formula II or III ((n) is 0 to 15; (x) is 1 to 8).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an adhesive composition of rubber and fiber, which is excellent in adhesiveness, heat resistance and heat resistance even if it does not contain an ethyleneimine compound which is not preferable in view of toxicity and malodor during treatment. The present invention relates to a method for producing a rubber reinforcing fiber having fatigue properties and the like.

[0002]

2. Description of the Related Art Nylon 6 fiber or nylon 6 is used as a reinforcing material for rubber structures such as tires, belts and hoses.
Synthetic fibers such as polyamide fibers represented by six fibers, polyester fibers represented by polyethylene terephthalate fibers, and aromatic polyamide fibers are used.

[0003] Polyester fibers and aromatic polyamide fibers are widely used as rubber reinforcing fibers because of their properties such as high specific strength, specific elastic modulus, and dimensional stability. Due to the inertness, there is a problem that the adhesiveness to rubber is poor as compared with nylon fibers.

[0004] As a technique for improving adhesion to rubber known so far, for example, as described in JP-A-5-148762, a polyester fiber is mixed with a mixture of resorcinol / formaldehyde / rubber latex, a triazine compound, There is a method of treating with a first treating solution comprising a polyepoxide compound and an ethyleneimine compound, and subsequently treating with a second treating solution comprising a mixture of resorcinol / formaldehyde / rubber latex.

Further, as described in JP-A-5-148760, an aromatic polyamide fiber is treated with a first treatment liquid comprising a mixture of resorcinol / formaldehyde / rubber latex, an ethyleneimine compound and a polyepoxide compound. Resorcinol / formaldehyde /
There is a method of treating with a second treatment liquid comprising a mixture of rubber latex and a phenolic compound.

[0006] However, although the adhesive strength is improved by these methods, the ethyleneimine compound has a risk of exhibiting symptoms such as red han, headache and nausea due to absorption into the skin, and furthermore, a malodor is generated during the treatment. Thorough measures must be taken for the exhaust during handling and processing, and this is not preferable for use in industrial practice.

On the other hand, as described in Japanese Patent Application Laid-Open No. Hei 8-100165, polyester fibers and aromatic polyamide fibers are treated with a first treatment liquid comprising a silicate compound, a polyepoxy compound, a blocked isocyanate compound and a rubber latex. Then, there is a method in which the mixture is treated with a second treatment liquid comprising a mixture of resorcinol, formaldehyde, and rubber latex.

However, this method has an advantage that excellent adhesive strength can be obtained even when the amount of the adhesive adhered to the fiber is reduced, but the heat resistant adhesive point is unsatisfactory because the amount of the adhesive adhered is small. Had the problem that

[0009]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems in the prior art, and provides an adhesive composition of rubber and fiber with an ethyleneimine compound which is not preferable in terms of toxicity and odor during treatment. A main object of the present invention is to provide a method for producing a rubber reinforcing fiber having adhesiveness, heat resistance, fatigue resistance and the like which are equal to or higher than that of an ethyleneimine compound-containing adhesive even if not contained.

[0010]

In order to achieve the above object, a method for producing a rubber reinforcing fiber according to the present invention comprises a method of producing a fiber comprising a polyepoxide compound, a blocked polyisocyanate compound, a rubber latex and a silicate compound. 1 treatment solution, then resorcinol, formaldehyde,
The treatment is performed with a second treatment liquid containing rubber latex (RFL) and a water-soluble urethane compound represented by the following general formula (I).

Embedded image (A is an aromatic polyisocyanate residue, X is a polyol residue, Y is a blocking agent residue, Z is a hydrophilic residue,
(L + m) is an integer of 2 to 4, l and m are 1 or more, and n is an integer of 1 to 4.

Further, the second processing liquid has the following general formula (I)
It is preferable to include the compound represented by I) or (III).

Embedded image (N represents 0 or an integer of 1 to 15)

Embedded image (X represents an integer of 1 to 8, n represents 0 or an integer of 1 to 15)

The dissociation temperature of the blocking agent residue (Y) in the compound of the general formula (I) is preferably from 130 to 200 ° C., and the mixing of RFL and the water-soluble urethane compound in the second treatment liquid. The ratio (weight ratio) is 100/5 to 5
It is preferably 100/30.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, fibers to be treated with an adhesive treatment liquid are in the form of filament yarn, cord, woven fabric, and braid made of synthetic fibers such as polyester fibers and aromatic polyamide fibers. It suffices that the surface of the fiber is coated with the effective components of the adhesive treatment liquids (the first treatment liquid and the second treatment liquid).

As the polyester fibers, those made of polyethylene terephthalate or a high molecular weight linear polyester mainly composed of ethylene terephthalate units are preferably used.

As the aromatic polyamide fiber, those made of poly-P-phenylene terephthalamide, poly-P-phenylene-3-4'-diphenyl ether terephthalamide, and a copolymer mainly composed of these are preferable. used.

Next, the composition of the bonding solution used in the present invention will be described.

First, the polyepoxide compound contained in the first treatment liquid is a polyglycidyl ether compound of a polyhydric alcohol and a compound containing two or more epoxy groups in one molecule. Specifically, glycerol, pentane Reaction products of polyhydric alcohols such as erythritol, sorbitol, ethylene glycol, polyethylene glycol, propylene glycol and polypropylene glycol with halogen-containing epoxides such as epichlorohydrin, resorcinol, bis (4-hydroxyphenyl) dimethylmethane, phenol. Bis- (3,4-epoxy-6-methyl-dicyclohexylmethyl) azibe, a reaction product of a polyhydric phenol such as formaldehyde resin and resorcinol-formaldehyde resin with the above-mentioned halogen-containing epoxides Refers to polyepoxide compounds obtained by oxidizing the unsaturated bond moiety such as 3,4-epoxy-cyclohexene epoxide. Preferably, a reaction product of a polyhydric alcohol and epichlorohydrin (a polyglycidyl ether compound of a polyhydric alcohol) is used.

Next, a blocked polyisocyanate compound is a compound which releases an active isocyanate compound by releasing a blocking agent by heat, and specifically, tolylene diisocyanate, metaphenylene diisocyanate,
Polyisocyanate compounds such as diphenyl methane diisocyanate, hexamethylin diisocyanate and triphenyl methane triisocyanate, and phenols such as phenol, cresol and resorcin; ε
-Lactams such as caprolactam and valerolactam,
Reaction products with a blocking agent selected from oximes such as acetoxime, methyl ethyl ketone oxime and cyclohexane oxime, and ethyleneimine.

Among these blocked polyisocyanate compounds, the use of an aromatic polyisocyanate compound blocked with ε-caprolactam and an aromatic compound of diphenylmethane diisocyanate give good results.

As the rubber latex, natural rubber latex, styrene / butadiene rubber latex,
Rubber latex such as acrylonitrile-butadiene rubber latex, chloroprene rubber latex, and vinylpyridine-styrene-butadiene rubber latex can be used, and these can be used alone or in combination.

Further, the silicate compound is preferably a synthesized hydrophilic silicate compound. Since the apparent viscosity of an aqueous solution of the synthesized hydrophilic silicate compound is increased, sedimentation and separation of the liquid are prevented. Since the particles hardly occur and the particles are fine, even in a low-concentration slurry, the uniform dispersibility of water and solid particles is large, and the adhesive component can be uniformly attached to the fiber surface. In addition, silicate compounds increase the cohesive force of the adhesive film, thereby improving the adhesive force, while improving the flexibility of the cord, thereby improving the fatigue resistance and greatly improving the properties of the rubber reinforcing fiber. Can be.

The second treatment liquid includes a mixture of resorcinol-formaldehyde precondensate and rubber latex (RF
L) and a water-soluble urethane compound.

The water-soluble urethane compound is a heat-reactive water-soluble urethane resin represented by the general formula (I),
Aromatic polyisocyanate residue A having a functionality of 3 to 5;
Compound having X (polyol residue) having four active hydrogen atoms, blocking agent residue Y releasing an isocyanate group by heat treatment, and hydrophilic residue Z having at least one active hydrogen atom or anion-forming group It is.

This water-soluble urethane compound can be treated with Y at the time of treatment.
The dissociation temperature of the blocking agent is preferably 130 ° C. or higher, and the temperature is preferably 200 ° C. or lower from the viewpoint of adhesiveness, since a part of the blocking agent is dissociated to generate a unique odor. The dissociation temperature of this blocking agent is determined by a differential thermal analyzer (T
DA) and a thermogravimetric measuring device (manufactured by Shimadzu Corporation) at a measuring temperature of 20 to 400 ° C. and a heating rate of 1
It is a value obtained by measuring under the conditions of 0 ° C./min and N ₂ gas in the measurement atmosphere.

Further, since the above-mentioned water-soluble urethane compound is water-soluble, it has good liquid stability when added to an aqueous solution of the adhesive component, and helps uniform adhesion of the adhesive component to the fiber surface.

It is also preferable to further compound a compound represented by the above general formula (II) or (III) as an adhesion improver.

The compound of the general formula (II) includes 2,
6-bis (2 ', 4'-dihydroxy-phenylmethyl) -4-chlorophenol (trade name: Vulkabond E, Denabond); and the compound of the general formula (III) includes halogenated phenol, formaldehyde and A compound derived from a phenol derivative or a polyhydric phenol and sulfur chloride (trade name: Sumikanol 75)
0) is used.

Next, the composition ratio of the first processing solution of the present invention will be described. The compounding ratio of the polyepoxide compound / blocked polyisocyanate compound / rubber latex of the present invention is 10 to 25% by weight / 20 to 35% by weight / 0 to 70% by weight, particularly 10 to 20% by weight / 20 to 30% by weight / 0
The ratio is preferably 70 to 70% by weight. If the blending amount of the polyepoxide compound / blocked polyisocyanate compound is too small, it becomes difficult to satisfy the initial adhesive strength.

The synthetic silicate compound may be 1 to 15% by weight based on 100% by weight of the mixture of the polyepoxide compound / blocked polyisocyanate compound / rubber latex, and the range of 3 to 10% by weight is particularly preferable. If the amount of the synthetic silicate compound is less than 1% by weight, the cord becomes hard, and if the amount exceeds 15% by weight, adhesive adhesion spots occur and the adhesive strength tends to decrease, which is not preferable.

The total solid content of the first processing solution is used at 3 to 15%, preferably 4 to 10%. If the solid content becomes too high, a problem arises in the stability of the liquid.

The mixture of the resorcinol-formaldehyde precondensate and the rubber latex of the second treatment liquid of the present invention is generally called RFL, and the precondensate of resorcinol and formaldehyde is obtained by using an alkali catalyst. The molar ratio of resorcinol to formaldehyde is 1: 0.3 to
The range is 1: 5, preferably 1: 0.75 to 1: 2.0. In using this novolak-type condensate of resorcinol and formaldehyde, it is preferable to dissolve in an aqueous alkali catalyst solution and then add formaldehyde to make the same molar ratio as resorcinol and formaldehyde initial condensate. The compounding ratio of the resorcinol formaldehyde precondensate and the rubber latex (L) is 1: 3 to solid content by weight.
1:12, preferably in the range of 1: 5 to 1: 9. Note that the same rubber latex as described above may be used.

The water-soluble urethane compound represented by the general formula (I) is added to the RFL in an amount of 5 to 30% by weight, preferably 10 to 25% by weight, based on 100% by weight of the RFL of the second treatment liquid. % Should be added. If it is less than 5% by weight, the degree of improvement in adhesive strength and heat resistance is small, and
If the content is more than 10% by weight, the improvement of the adhesive strength reaches a saturated state, and a negative effect such as hardening of a cord occurs.

When the compound represented by the general formula (II) or (III) is added to the mixed solution of the RFL and the water-soluble urethane compound for improving the adhesion, the RFL of the second processing solution is preferably 100% by weight. 10 to 35% by weight, preferably 15 to 30% by weight. If the amount is less than 10% by weight, it is not desired to improve the adhesive strength.

The total solid content of the second processing solution is used at 5 to 20%, preferably 7 to 15%. When the solid content concentration increases, a problem arises in the stability of the liquid. In order to attach the first treatment liquid and the second treatment liquid to the fibers, any method such as immersion, nozzle spraying, or application with a roller may be used.

The adhesion ratio of the adhesive composition to the polyester fiber (total of the first treatment and the second treatment) is 1.5 to 4.5% by weight based on the polyester fiber in a dry weight ratio. 2.0-3.5% by weight is optimal. 1.5% by weight
If it is less than the above, the adhesive strength is undesirably reduced. Also, 4.
If it exceeds 5% by weight, fatigue resistance and heat resistance are reduced.

The adhesion ratio of the adhesive composition to the aromatic polyamide fiber is 3.0 to 6.0% by weight based on the weight of the aromatic polyamide fiber fiber, and among them, 3.5 to 5.0.
0% by weight is optimal. If it is less than 3.0% by weight, the adhesive strength is undesirably reduced. On the other hand, if it exceeds 6.0% by weight, fatigue resistance and heat resistance are reduced.

Applying a mixture of the first treatment liquid to the fibers,
After drying at 70 to 150 ° C., heat treatment is performed at 200 to 245 ° C., followed by applying the second treatment liquid, drying at 70 to 150 ° C. like the first treatment liquid, and performing heat treatment at 200 to 255 ° C.

[0038]

Next, the present invention will be specifically described with reference to examples. Each measurement value was obtained by the following method.

(1) T-Initial Adhesive Strength and T-Heat Resistant Adhesive Strength A treatment code is embedded in unvulcanized rubber under the following conditions in accordance with the adhesive strength-A method of JIS L-1017 (1983).
Press vulcanization is performed under pressure at an initial adhesive strength of 150 ° C. for 30 minutes and at a heat resistant adhesive strength of 170 ° C. for 16 hours. After cooling, the cord is pulled out of the rubber block at a speed of 30 cm / min. Indicated in cm. As the unvulcanized rubber, general carcass compound rubber for automobile tires was used.

(2) Peeling Adhesion and Hot Peeling Adhesion Two topping sheets each having a processing cord embedded in a carcass compounded rubber for general automobile tires at a density of 26 / inch so that the processing cords are parallel to each other. Lamination, 15
Press vulcanization at 0 ° C for 30 minutes
A normal peel test was performed at 20 ° C., and a hot peel test was performed at a speed of 5 cm / min in an environment of 70 ° C., and the peel load was expressed in Kg / 2 cm.

(3) JIS L-1017 (19)
1983).

(4) Fatigue Resistance (Good Rich Method Disk Fatigue) According to JIS L-1017 (1983), a rubber block filled with polyester fibers is stretched 5% in elongation and 2% in compression.
The disk was mounted around two disks tilted to 0%, and the strength retention after repeated fatigue at 1705 rpm for 48 hours was expressed as a percentage. In the case of aromatic polyamide fiber, elongation is 0%, compression is 12%, and 1705r
The strength retention rate after fatigue for 6 hours in pm was indicated by 100 minutes. The rubber compound used is the same compound used for the bonding.

(5) Odor at the time of treatment The odor generated when the fiber is heat-treated with the second treatment liquid is judged by human olfaction.
It is represented by

Examples 1 to 5 A first bath treatment liquid was prepared by adding water to polyglycerol polyglycidyl ether (polyepoxide compound) and emulsifying the mixture using a homogenizer, and an aromatic polyether blocked with ε-caprolactam. An isocyanate compound (blocked polyisocyanate compound), vinylpyridine-styrene-butadiene latex, and a 1% aqueous dispersion of a synthetic silicate compound were mixed at a predetermined ratio shown in Table 1, and the liquid solids concentration was 5%. .5
% Of the first bath treatment liquid was obtained.

As a second bath treatment liquid, an initial condensate obtained by reacting 2.0 mol of formaldehyde with 1 mol of resorcinol in the presence of caustic soda and a vinylpyridine-styrene-butadiene latex as shown in Table 1 The mixture was mixed at a predetermined ratio and aged for 24 hours. This treatment liquid was mixed with the following water-soluble urethane compound and, if necessary, the compounds of the following general formulas (II) and (III) to obtain a second treatment liquid having a liquid solid concentration of 10%. .

Water-soluble urethane compound: In the above-mentioned general formula (I), A = polymethylene polyphenyl polyisocyanate, X = 2 mol adduct of ethylene oxide of bisphenol A, Y = blocking agent having a dissociation temperature of 180 ° C., Z = Taurine soda, n = 2-4, l + m = 2-4
The compound of the general formula (II): “Denabond” (manufactured by Nagase Kasei Kogyo Co., Ltd.) The compound of the general formula (III): “Sumikanol 750”
(Sumitomo Chemical Industries, Ltd.)

Two 1500-denier multifilament yarns obtained by melt-spinning and drawing polyethylene terephthalate having an intrinsic viscosity of 0.95 were plied in a twist of 40 turns / 10 cm,
The raw cord was twisted at a twist number of 40 times / 10 cm. Next, the raw code was immersed in the first treatment liquid using a computer treater (manufactured by Ritzler),
It was dried at 30 ° C. for 150 seconds and subsequently heat-treated at 240 ° C. for 60 seconds. Next, after being immersed in the second treatment liquid, the resultant was dried at 100 ° C. for 150 seconds, and then heat-treated at 230 ° C. for 60 seconds. The adhesion amount of the first bath treatment liquid in the obtained treatment code was 1.
The amount was 3% by weight, and the amount of the second treatment liquid attached was 1.5% by weight.

Table 1 shows the results of measuring the T-adhesive strength, peel adhesive strength, cord strength, and odor during treatment of the treated cord.
It was shown to.

[Comparative Examples 1 and 2] Comparative Example 1 did not include the silicate compound of the example, and Comparative Example 2 changed the water-soluble urethane compound of the example to an ethyleneimine compound. And processed under the same conditions as in Examples 1 to 5 except for the above, and the results are shown in Table 1. As shown in Table 1, the polyester fiber for rubber reinforcement treated according to the present invention has the same or higher adhesiveness as the conventional one.
It has heat resistance and fatigue resistance, and can eliminate the bad smell during the treatment peculiar to the conventional ethyleneimine compound.

[0050]

[Table 1]

[Examples 6 to 8] Multifilament yarn of aromatic polyamide fiber having a display fineness of 1500 denier and 1000 filaments ("Kevlar" manufactured by DuPont)
Twisted 35 times / 10cm, Twisted 35 times / 10cm
And the raw cord was twisted with the number of twists. The raw cord was immersed in a first treatment liquid mixed with the composition shown in Table 2 using a computer treater (manufactured by Ritzler), and then heated at 130 ° C.
For 150 seconds, followed by heat treatment at 240 ° C. for 60 seconds. Next, after being immersed in the second treatment liquid mixed according to the formulation shown in Table 2, dried at 100 ° C. for 150 seconds, and then dried at 230 ° C. for 60 seconds.
Heat treated for seconds. The adhesion amount of the first bath treatment liquid of the obtained treatment code was 2.5% by weight, and the adhesion amount of the second treatment liquid was 2.0% by weight.

Table 2 shows the results of measuring T-adhesive strength, cord strength, fatigue resistance, and odor during the treatment of the treated cord.

Comparative Examples 3 and 4 Comparative Example 3 did not include the silicate compound of the example, and Comparative Example 4 changed the water-soluble urethane compound of the example to an ethyleneimine compound. , And processed under the same conditions as in Examples 1 to 5 except for the above. The results are shown in Table 2. As shown in Table 2, the rubber-reinforcing aromatic polyamide fiber treated according to the present invention has the same or higher adhesiveness, heat resistance and fatigue resistance as those of the conventional one, and has the same properties as those of the conventional ethyleneimine compound. The odor was eliminated.

[0054]

[Table 2]

[0055]

The rubber reinforcing fiber obtained by the treatment according to the present invention is free from the problems of the toxicity of the conventional ethyleneimine compound and offensive odor during the treatment, and is at least as good as the adhesive containing the ethyleneimine compound. It has adhesiveness, heat resistance and fatigue resistance.

Claims (5)

[Claims] 1. The fiber is treated with a first treating solution containing a polyepoxide compound, a blocked polyisocyanate compound, a rubber latex and a silicate compound, and then resorcinol-formaldehyde rubber latex (RFL)
And a water-soluble urethane compound represented by the following general formula (I). Embedded image (A is an aromatic polyisocyanate residue, X is a polyol residue, Y is a blocking agent residue, Z is a hydrophilic residue,
(L + m) is an integer of 2 to 4, l and m are 1 or more, and n is an integer of 1 to 4. 2. The method according to claim 1, wherein the second treatment liquid further contains a compound represented by the following general formula (II) or (III). Embedded image (N represents 0 or an integer of 1 to 15) (X represents an integer of 1 to 8, n represents 0 or an integer of 1 to 15) 3. The mixing ratio (weight ratio) of RFL and water-soluble urethane compound in the second treatment liquid is 100/5 to 10
The method for producing a rubber reinforcing fiber according to claim 1 or 2, wherein the ratio is 0/30. 4. The method for producing a rubber reinforcing fiber according to claim 1, wherein the dissociation temperature of the blocking agent residue (Y) in the general formula (I) is 130 to 200 ° C. . 5. The method for producing a rubber reinforcing fiber according to claim 1, wherein the rubber reinforcing fiber is a polyester fiber or an aromatic polyamide fiber.